1. Field of Invention
The present invention relates to a measuring graduation for a position measuring system having a base body formed of a permanently magnetizable material, extending in a measuring direction, and having first and second sections alternatingly arranged one after another in the measuring direction and having, respectively, first and second magnetization directions, with a position information being generated by a sensor displaceable relative to the base body in the measuring direction for scanning the same. The present invention also relates to a position measuring system with the inventive measuring graduation and to a method of magnetizing the base body of the measuring graduation.
2. Description of the Prior Art
In measuring graduations of the type described above, the base body, which serves as a graduation support, is formed advantageously as a one-piece part with a predetermined magnetic structure forming a graduation standard. The magnetic structure is produced by magnetization of the base body, whereby the base body, viewed in a predetermined measuring direction, has first sections having a first magnetization direction and second sections having at least one further magnetization direction. The first and second sections are so alternatingly arranged one behind the other that a position information is generated by a sensor displaceable relative to the base body in the predetermined measuring direction. With this, on one hand, an absolute position information can be obtained when the magnetization of the base body produces a code.
With the sensor scanning the code, for each position of the sensor relative to the base body, the position of the sensor is singularly defined. On the other hand, the magnetic structure of the base body can be used for producing an incremental track which enables to easily determine the change of a position of a sensor relative to the base body.
Here, permanently magnetizable material is a magnetic material in which a location-dependent magnetization is produced by one or several outer magnetic fields and which is retained when the base body is not subjected to the action of the one or several magnetic fields. A base body formed of a permanently magnetizable material is, thus, suitable for use in position measuring systems.
A problem with a magnetic base body with a predetermined magnetic structure (location-dependent magnetization) consists in producing of a magnetic structure which would have, viewing in a measuring direction, arranged one after another sections with a different magnetization direction and which would have, respectively, a definite, predetermined magnitude necessary for a precise determination of a position. Therefore, for forming a magnetic measuring graduation often a two-part base body is used, with the two parts being magnetized independently of each other and then assembled with each other, with one part forming sections with first magnetization direction and the other part forming sections with a second magnetization direction.
An object of the present invention is a measuring graduation of the type described above which has a simple construction and which can be easily produced.